More than 1,500 children lost one or both parents in the disaster - and they're still struggling to come to grips with what happened that awful day.

What we see of the tsunami's effects is horrific. What we can't see can be just as devastating.

Naho Abe's family was just her and her mother. When the tsunami raced through, she was swept up, but managed to survive. Her mother was swept away. Pictures are all the 18-year-old has of her mother now.

She told us she has waves of emotions she struggles to control. Sometimes, she said, it's hard.

After the tsunami, in relief shelters, you couldn't help but notice all the children. Some 20,000 are still homeless.

"Lots of children were displaced very rapidly and under very frightening circumstances," points out Irwin Redlener, director of the National Center for Disaster Preparedness at Columbia University. He studies the effects of disasters on children.

"There's a myth that the disaster's over when the rains stop, or the earthquake finally settles down," he said. "But the fact is, for children ... the consequences of disaster can last for many, many years, and possibly never go away."

UCLA pediatrician Kozue Shimabukuro raced back to her native Japan after the tsunami, to help the children. "The patients I encountered during that time were just so heartbreaking," she recalls. "They just hold onto me and say, 'Don't go, don't go,' like they can't endure to lose another person in my life."

Doctors from Israel still are here helping children with PTSD. U.S.-based World Vision set up seven Child-Friendly Spaces. Some children escaped their school just before the tsunami washed through.

In a year when the world for these children has been chaotic and stressful, they're proving here that creating an environment that's warm and stable can make a world of difference.

World Vision's Rachel Wolff says, "To have a place that's their own, where there's teachers and volunteers that can work with them, can really help the healing process."

Naho Abe says she's healing, thanks to counseling and financial support from Ashinaga, a charity that helps children who've lost parents. Inspired by the help she's received, she plans to go to medical school so she can help others in need.

To see Bill Whitaker's report, click on the video in the player above.